Definitely worth it. You can use it for almost ANY firearm over 50 years old, not just military surplus. See item 1 below. That currently means anything before 1968. If you buy more than one a year, it pays for itself. The following is copied from the rule from the current BATFE circular on the 03 FFL:

It's not even been a remote consideration for me in the past, as I've always done good on the street, FTF. I've been at it for a few decades, and prefer to handle and inspect each item. BUT, the world wide web has added an impact with a greater base of availability. I haven't acquired an 03, and don't intend to, as I'm a Kali resident and you need a COE (more shake down fee$), and must pay a self registration fee of $19 bucks per item. In 2015 Kali did away with C&R cash & carry. My long time FFL charges a flat rate weather it's 1 or 5 guns to receive from out of state, and will accept from a private party. I've been into SKSs for a while, and until the Sinobanians showed up a few years back, Chinese SKS didn't qualify as C&R anyway. Good for some, not for me. PAX

I got a C&R when I first started getting into collecting. At the time, Midway, Graf's, Brownells, and others would give dealer pricing if you sent in the C&R. I saved the equivalent of the license fee on my first order from Midway for reloading equipment and supplies! Not sure if they are still doing that now, as I let my license lapse, and haven't had the funds to do much loading or shooting lately.

I had one for 9 years starting in 2007. Back then, Midway would give you dealer pricing if you had one and the savings were pretty significant. I saved several hundred dollars on an AR15 upper I bought from them which paid for the license several times over. They don't do that anymore though, nor do most other online retailers. My tastes have moved on to Antiques where no license is needed at all. I dropped it after the ATF started asking you how many C&R arms you sold since your last renewal.